StarlingX: Variable Subsitution of System Paths

Storyboard: https://storyboard.openstack.org/#!/story/2004039

The Multi-OS effort requires that we can modify the locations that some files might be found during installation and later for configuration. While the Linux Standard Base (LSB) includes the Filesystem Hierarchy Standard (FHS) not all Linux distributions follow it exactly, therefore there can be differences.

Problem description

Many scripts and configuration files hardcode certain paths and filenames, depending on the Linux distribution these may not be accurate from one distribution to the next. By providing a mechanism for variable substitution during build, installation or update, this problem can be addressed.

Use Cases

This is for the Developer and system level engineer working on implementing changes to support OS independence in the StarlingX service (Flock) and system level configuration files contained within StarlingX stx repos.

Proposed change

Using the existing naming conventions, change the existing hardcode paths to the common naming convention and then do substitution via sed or other tool as appropriate. This renaming could occur in any source or configuration file, not limited to Makefiles, .ini, .config, or scripts.

Examples:

RPM Variable Make Variable Substitution Variable %{_sysconfdir} SYSCONFDIR @SYSCONFDIR@ %{_buildroot} DESTDIR @DESTDIR@ %{pythonroot} PYTHONROOT @PYTHONROOT@

Posting to get preliminary feedback on the scope of this spec.

Alternatives

None

Data model impact

None

REST API impact

None

Security impact

None

Other end user impact

None

Performance Impact

None

Other deployer impact

No additional configuration options are being added, but existing ones may change based on how the variables are substituted.

Developer impact

Developers will need to be aware of the variables and how they get substituted and added. This can be addressed in the Developer Guide Wiki.

Upgrade impact

None

Implementation

Assignee(s)

Primary assignee:

Shuicheng Lin (shuicheng)

Other contributors:

Mingyuan Qi Zhipeng Liu Saul Wold (sgw-starlingx)

Repos Impacted

stx-clients stx-config stx-fault stx-gui stx-ha stx-integ stx-metal stx-nfv stx-update stx-upstream

Work Items

Initial work:
Ongoing Discovery

  • Create additional tasks in the 2004039 Story as we discover additional hardcoded paths that need substitution.

  • Ensure that the StarlingX services are using the correct LSB/FHS directory structure as implemented by the upstream distribution (this can still vary slightly).

Dependencies

None

Testing

Verify configuration is correct before and after the change and test that the resulting system boots correctly and has the correct configuration.

Documentation Impact

Developer Guide Wiki will need to be updated to list the canonical variables and their default paths.

References

Linux Standard Base: https://wiki.linuxfoundation.org/lsb/start Hierarchy Filesystem Standard: https://wiki.linuxfoundation.org/lsb/fhs

History

Revisions

Release Name

Description

2019.03

Introduced